Residents of Owino Uhuru slums have sued a government agency, seeking Sh1.6 billion compensation after they suffered lead poisoning.
They accused the National Environment Management Authority (Nema) of failing to heed calls to close down a lead factory in the area.
The villagers told the High Court that Nema licensed Metal Refinery Ltd to set up its factory near homes, well aware that its activities would affect them.
Alfred Mulo, 70, said more than 3,000 people had suffered lead poisoning and demanded that the environmental agency share the blame with the firm.
In the suit before Justice Ann Amollo, the residents also want the agency to pay for their treatment.
They said they had developed respiratory diseases and other health complications after they were exposed to lead emissions from the battery smelting plant that has since been closed down.
Nine villagers, through the Centre for Justice, Governance and Environmental Action, filed the petition demanding compensation in 2016.
Other respondents in the matter are the Attorney General, the Cabinet secretaries in the ministries of Environment, Health, Water and Natural Resources, the county government of Mombasa, the Export Processing Zones Authority, Metal Refinery EPZ Ltd, and Penguin Paper and Book Company.
Mr Mulo testified that Metal Refinery Ltd started smelting batteries in the slums that has more than 200 households in 2007.
He said the residents were not consulted before the factory was set up.
"Soon after the company started its operations, the roofs of our houses began rusting and wearing out. Many people started falling sick," Mulo told court.
"The factory emitted dark smoke and brown waste water that ended up in the village. Animals that drunk the water died."
In 2009, Mulo said, the residents held demonstrations against the factory's activities and complained to Nema and the local administration, but no action was taken.
"When health officials tested residents, they found them with high levels of lead poisoning. They also said the soil had been polluted with six feet of lead,” said Mulo.
The petitioners’ lawyer, Charles Onyango, said he would call seven experts to testify and demonstrate the levels of lead poison in the village and how it had affected residents.
Petitioners want a declaration that their right to life was violated by the actions, inaction and omissions of the respondents.
They want the respondents ordered to clean up the area, get rid of the lead and finance their treatment.
Mulo said his family of two wives and nine children was affected.
“When I was tested, it was found that I had lead poison of 38.2 milligrammes per decimal. I became anaemic. I was always coughing and stayed in the hospital for a long time,” said Mulo.
Another resident, Scolastica Sikanga, told the court her grandchild fell ill after he stepped into water contaminated with lead.
"I would have left the area but I do not have the means. However, I took my grandchild to a children's home far away to save his life," she said.
Nema, through lawyer Linda Kosgei, denied responsibility and claimed it had ordered the closure of the factory in 2013.
The factory was established to collect used batteries for smelting.
Expert analysis has indicated that carbon compounds produced during the process contaminated food and dwellings around Owino Uhuru slums through effluent and smoke.